Scanner Guide Shaft Grounding in a Compact Image Reader
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Solution Overview
Problem
Conventional image reading apparatuses face the challenge of increased external size due to the requirement of space for grounding members at the end portion of the guide shaft, which supports the reading unit.
Innovation Solution
The apparatus employs a resin housing with a sliding portion on the guide shaft that includes a groove-like shape for grounding, allowing the guide shaft to be grounded without enlarging the apparatus size, using grounding springs that contact the guide shaft within and outside the scanning region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a grounding member is added at the end portion of the guide shaft, then the guide shaft can be grounded to suppress electromagnetic interference, but the external size of the image reading apparatus becomes larger
Solution Approach 1:
The grounding member is repositioned from the end portion of the guide shaft to the sliding portion that fits onto the guide shaft. This spatial repositioning allows the grounding function to be achieved within the existing axial space of the guide shaft, eliminating the need to extend the apparatus housing in the axial direction.
Solution Approach 2:
The sliding portion is designed to serve multiple functions: it provides mechanical support for the reading unit, enables sliding motion along the guide shaft, and simultaneously serves as the mounting location for the grounding member. This multi-functionality eliminates the need for separate end-portion grounding structures.
2Weight of stationary object
If the housing is made from resin to reduce weight and cost, then manufacturing cost and weight are reduced, but electromagnetic shielding capability is weakened
Solution Approach 1:
The electromagnetic shielding function is segmented from the housing structure and assigned to a dedicated grounding member made of conductive material. This allows the housing to remain lightweight resin while the grounding member provides targeted electromagnetic interference suppression at critical locations.
Solution Approach 2:
The apparatus employs a composite structure combining resin housing with metal grounding members. The resin provides lightweight construction and cost benefits, while the metal grounding members provide electromagnetic shielding, creating a hybrid structure that leverages the advantages of both materials.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively suppresses electromagnetic interference waves while maintaining a compact size, ensuring efficient operation without increasing the external dimensions of the image reading apparatus.
Implementation Method 1
a grounding member configured to ground the guide shaft by being in contact with the guide shaft
Implementation Method 2
the holding member includes a sliding portion that fits to the guide shaft and is slidable in the scanning direction with respect to the guide shaft
Data Source
AI summary
Disclosed is an image reading apparatus including: a reading unit for reading a document placed on a transparent plate while moving in a scanning direction; a holding member for holding the reading unit; a guide shaft for supporting the holding member such that the holding member can move in the scanning direction; a housing for accommodating the reading unit and the guide shaft, the transparent plate being placed on an upper surface of the housing; and a grounding member for grounding the guide shaft by being in contact with the guide shaft. The holding member includes a sliding portion that fits to the guide shaft and is slidable in the scanning direction with respect to the guide shaft, the sliding portion having a groove-like shape whose lower portion is opened. The grounding member is in contact with the guide shaft in an opened portion of the sliding portion.